Letters to the editor

» Re: Edible candle, September 2017

To add to the discussion on the edible candle demonstration, I have been doing it for almost four decades, catching full attention during the first week of school each year. Early on, I found the taste of raw potato to be distasteful enough that I experimented around. I found that pear worked just as well, as long as the column, cut with an apple corer, was kept in a pressure-sealed bag to prevent oxidation. About a decade ago, I found that a section of a stringed cheese tube works even better. (I once had a student ask the next day if I had eaten a raw potato candle, and I was able to honestly state that I had not.)

As an aside, when students query whether I am going to be out sick the next day, I sidetrack their thought by telling a different but true tale. When my eldest child was an infant (she is now 40 years old), she had a habit of eating crayons. The colored wax passed through her system, which was evident when I changed her diapers. That usually ends the questioning and adds to the erroneous mindset of their observations.

I don't disclose the actual composition of the candle, as that would interfere with future years' demonstrations.
I later stress the need to be careful about the observations they make, using other contexts to get the message across.

Avi Ornstein, Classical Magnet School,

Hartford, Connecticut    

» Re: “Lab safety and common sense…” and
    “Who Knew?” October 2017

I read with a great deal of enjoyment the article by Michael Jansen and the subsequent STAO (Science Teachers’ Association of Ontario) response. First, kudos to Jansen for penning what many of us noted was total overkill on safety precautions. The response by David Gervais, Chair of the STAO Safety Committee, suggests the onus is on the teacher to extract from an excessive list of dos and don'ts, those that apply. This begs the question as to whether the STAO drafted the list of safety precautions lest there be possible blowback onto STAO should an accident occur.

Perhaps to placate everyone, the STAO virtual library can publish a separate document on general safety where all of these suggestions can be listed. Then in the actual demo, the only safety advice that need be given is to make certain the almond has cooled before eating!

In the same issue, Lew Brubacher's Pepto Bismol tongue is only one of the side effects of taking the pink liquid. While it is sold to relieve stomach pain from excess acid,it also contains significant amounts of salicylic acid.1 This is counter-intuitive as salicylic acid (SA) is hard on the stomach and is contraindicated if one has an ulcer.1,2 It can also contribute to stomach bleeding.2 The acetylated version, ASA, was designed to allay the harshness of SA.

Pepto Bismol, in addition to bismuth subsalicylate, which produces salicylic acid upon hydrolysis in the stomach,3 includes (as inactive ingredients) sodium salicylate and salicylic acid.1

There are numerous other antacids on the market that will not contribute to digestive tract bleeding, exacerbate an ulcer nor they affect the colour of your tongue or stools.


  1. http://bodyandhealth.canada.com/drug/getdrug/pepto-bismol
  2. www.drugs.com/mtm/pepto-bismol.html
  3. www.drugbank.ca/drugs/DB01294   

Lyle Sadavoy, retired, Toronto, Ontario   

Re: “Lab safety and common sense not mutually exclusive”, October 2017.

Mr. Jansen’s comment reveals, perhaps, the greatest weakness in Canadian Initial Teacher Education (ITE) programs: a dearth of chemistry knowledge. I can illustrate this weakness in three points.

Unlike many large American universities, where chemical education constitutes a common sub-discipline within departments of chemistry and/or graduate studies, this is not the case in Canada. Speaking from personal experience at a major Canadian ITE and research university, I found what little focus there was on chemical education came from the chemistry department and not the education department. We can safely infer that chemistry knowledge is not bestowed upon chemistry teachers in ITE programs at Canadian universities.

In 2014, I attended the Biennial Conference on Chemical Education at Grand Valley State University, in Grand Rapids, MI. GVSU is one of those large American universities that focuses on chemical education. Greg Rushton, of Stony Brook University gave an illuminating lecture on the state of training amongst high school chemistry teachers.1 A precis of his talk is chemistry teachers often do not possess chemistry knowledge because they lack adequate instruction as chemists. Theodore Hodapp, American Physical Society Director of Education and Outreach from 2004 until 2016, made similar assertions in 2012 at the Physics Teacher Education Coalition: Among California high school science teachers, 72% of biology teachers were content-area trained, in contrast to 47% of physics teachers and 46% of chemistry teachers.2 If “common” means greater than 50%, then chemistry knowledge among California high school teachers is uncommon. When considering that “The American Institute of Physics says the average number of physics graduates for a bachelor granting institution… is 6.4 per year”3 it is not surprising that so few teachers acquire content expertise in the “hard” sciences.

At the risk of offending by non sequitur, I can provide only circumstantial antecedents for a lack of chemistry knowledge among Canadian high school chemistry teachers. The content knowledge requirements in five Canadian jurisdictions for specialization in chemistry in a Bachelor of Education program are as follows: Ontario — six full-year courses; British Columbia — five full-year courses; Saskatchewan — four full-year courses; Manitoba and Alberta — no courses required, as there is no chemistry specialization.4 It is worth noting that in Ontario, six courses are required only for a teacher’s first specialization. The requirements for a teacher already holding certification in another science is three full-year courses in chemistry.

Chemistry sits atop the cusp of science and art. No greater proponent of this viewpoint is Prof. Roald Hoffmann, who, through his writing in “The Same and Not the Same” and “Roald Hoffman on the Philosophy, Art, and Science of Chemistry”, serves to illustrate the fuzziness of the “science” of chemistry. It is just this fuzziness — art, if you will — in concert with reductionist physical science that dictates a unique pedagogical content knowledge that is the domain of the chemistry content-specialist-cum-pedagogue. Chemists can acquire pedagogical knowledge, just as the pedagogue can acquire chemical knowledge through dedicated study, perhaps not 10,000 hours, but much closer to that datum than zero. The question follows: who faces the longer journey, the chemi-gogue or the pedagogue? My suspicion is that Jansen’s irony is intentional.

Ken Hoffman, Rocky View Schools,

Airdrie, Alberta    


References: (online accessed November 2017)

  1. G. Rushton, H. Ray, B. Criswell, S. Polizzi, C. Bearss, N. Levelsmier, H. Chhita and M. Kirchhoff, Stemming the diffusion of responsibility: A longitudinal case study of America’s chemistry teachers. Educational Researcher, 2014, pages 390-403.
  2. T. Hodapp, New Paradigms for Physics Teacher Education, 2012 Physics Teacher Education Coalition Conference, Physics Teacher Education Coalition. www.compadre.org/Phystec/items/detail.cfm?ID=11692
  3. Rhett Allain, A New Record for Physics Graduates, Wired, 2016, www.wired.com/2016/05/new-record-number-physics-graduates/
  4. This information was culled from the respective provincial education authorities, except for British Columbia and Saskatchewan, where the information was obtained from the University of British Columbia and University of Saskatchewan Faculty of Education websites.